Word does not really have the ability to perform a "multiple items per
condition (=key field)" mailmerge.  In your case that would be multiple
committees per person.

See the "Multiple items per condition" item under the "Special merges"
section of fellow MVP Cindy Meister's website at

http://homepage.swissonline.ch/cindymeister/MergFram.htm

Or take a look at the following Knowledge Base Article

How to Work Around Duplicate Names in Mail Merge Data

http://support.microsoft.com/default.aspx?scid=kb;en-us;302665

Or, if you create a Catalog (on in Word XP and later, it's called Directory)
type mailmerge main document with the mergefields in the cells of a one row
table in the mailmerge main document with the keyfield in the first cell in
the row and then execute that merge to a new document and then run the
following macro, it will create separate tables with the records for each
key field in them.  With a bit of further development, you may be able to
get it to do what you want.

' Macro to create multiple items per condition in separate tables from a
directory type mailmerge

Dim source As Document, target As Document, scat As Range, tcat As Range
Dim data As Range, stab As Table, ttab As Table
Dim i As Long, j As Long, k As Long, n As Long
Set source = ActiveDocument
Set target = Documents.Add
Set stab = source.Tables(1)
k = stab.Columns.Count
Set ttab = target.Tables.Add(Range:=Selection.Range, numrows:=1,
numcolumns:=k - 1)
Set scat = stab.Cell(1, 1).Range
scat.End = scat.End - 1
ttab.Cell(1, 1).Range = scat
j = ttab.Rows.Count
For i = 1 To stab.Rows.Count
   Set tcat = ttab.Cell(j, 1).Range
   tcat.End = tcat.End - 1
   Set scat = stab.Cell(i, 1).Range
   scat.End = scat.End - 1
   If scat <> tcat Then
       ttab.Rows.Add
       j = ttab.Rows.Count
       ttab.Cell(j, 1).Range = scat
       ttab.Cell(j, 1).Range.Paragraphs(1).PageBreakBefore = True
       ttab.Rows.Add
       ttab.Cell(j + 1, 1).Range.Paragraphs(1).PageBreakBefore = False
       For n = 2 To k
           Set data = stab.Cell(i, n).Range
           data.End = data.End - 1
           ttab.Cell(ttab.Rows.Count, n - 1).Range = data
       Next n
   Else
       ttab.Rows.Add
       For n = 2 To k
           Set data = stab.Cell(i, n).Range
           data.End = data.End - 1
           ttab.Cell(ttab.Rows.Count, n - 1).Range = data
       Next n
   End If
Next i